1. Field of the Invention
Magnetic memory devices plated with magnetic materials and a process and apparatus for producing such devices.
2. Description of the Prior Art
Plated wire memory devices are those in which information is permanently stored in the magnetization, in a preferred direction, of a magnetic coating plated on a conductor wire. While such devices are known in the prior art, they have been of limited effectiveness. The effectiveness of such a device depends on its ability to produce high signal output in response to read out impulses but which retain the level of the stored magnetic information undiminished after long periods of repeated read out operations. This property is termed nondestructive read out, usually referred to as NDRO. The NDRO properties of a plated wire memory device are directly related to the magnitude of the anisotropy field parameter of the plated magnetic material. This parameter is well known and is represented by the symbol H.sub.K and expressed numerically in oersteds. The strength of the output signal, however, depends on the ease with which the stored magnetic vector can be tilted temporarily from its position along the preferred magnetic direction. While low values of H.sub.K make tilting of the magnetic vector relatively easy, such low values make for poor NDRO properties. The prior art has encountered difficulties in reconciling these two opposing requirements for an effective device.
Prior art attempts at producing satisfactory magnetically plated wire memory devices have suffered from such additional problems as poor reproducibility, inconsistent properties, low yields of acceptable lengths of plated wires, and the inability of the plated wire to store closely spaced magnetic bits of information. Such wires are said to have low ABI resistance. The term ABI stands for "adjacent bit interference".